<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
	</head>
	<body>
		<ul>
			<li class="one"></li>
			<li class="one"></li>
			<li class="one"></li>
			<li class="one two"></li>
			<li class="one three"></li>
			<li class="one"><img src="https://gss0.baidu.com/-vo3dSag_xI4khGko9WTAnF6hhy/zhidao/pic/item/562c11dfa9ec8a135ea6851bf103918fa1ecc089.jpg"/></li>
		</ul>
	</body>
	<script src="http://libs.baidu.com/jquery/2.0.0/jquery.min.js"></script>
	<script type="text/javascript">
//		if($(".one").hasClass("two")){
//			alert("ok")
//			$('.one').addClass("hahah")
//		}else{
//			alert("err")
//		}
		var arr = ["5", "6", "19", "20", "21", "24", "27", "28", "30", "31", "9", "10", "11", "19", "20", "21", "24", "25", "27", "28"];
		console.log(arr.indexOf("25")==-1);
		console.log(typeof(arr.indexOf("25")));
	</script>
</html>
